Expression of P-53 and P-Glycoprotein in
Paediatric Non Hodgkin's Lymphoma

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Abstract:

Non Hodgkin's Lymphoma (NEIL) are among the most common tumours in Egyptian
children. Clinicopathologic features does not always predict the response to chemotherapy
or survival. Among the important factors affecting prognosis in NHL is multidrug resistance
(MDR). The overexpression of P-glycoprotein is the most important mechanism
of drug resistance, which encodes the MDR! gene. Other factors include overexpression
of the nuclear phosphoprotein encoding the P-53 suppressor gene as well as overexpression
of the Bc1-2 gene product. This study included 20 patients pathologically diagnosed
as NEIL and presenting to the National Cancver Institute, Cairo University during the period
1991-1995. The present study investigated P-glycoprotein, P053 and Bc12 oncoproteins
by immunohistochemical techniques, being important biological factors involved in
the process of lymphoma. P-glycoprotein was positive in 25% of cases and P-53 in 40%
of cases. Bc1-2 was negative in all cases studied. Positivity for P-glycoprotein and P-53
were mostly in high grade malignancy, representing 80% and 87.5% of positive cases respectively.
P-53 positivity was highest in Burkitt's lymphoma with significant difference
from the Burkitt-like small non cleaved type. Response to treatment and survival were affected,
as 80% of P-glycoprotein and 87.5% of P-53 positive cases died from increasing
disease. On the contrary, 60% of P-glycoprotein and 75% of P-53 negative cases achieved
complete remission (CR) and are alive. Coexpression of both P-glycoprotein and P-53 in
NHL patients was of poorer prognosis, confirming the suggested association between
MDR and P-r3 proteins. In conclusion: P-53 positive reaction bears a poor prognosis in
NHL. P-glycoprotein and P-53 can be used for identification of patients requiring more
intensive chemotherapy, or regimens containing drugs not extruded by the MDR pump.
Hence, i proved outcome of NHL can be achieved.